#2018年省赛-填空题 猴子分香蕉
for i in range(1, 10000):
    #总量-吃掉的（多余的）除以5（分五堆）乘以4（藏一份后剩余的）
    a = (i - 1) * 0.8
    b = (a - 2) * 0.8
    c = (b - 3) * 0.8
    d = (c - 4) * 0.8
    if d % 5 == 0 and d != 0:
        print(i)
        break
